That's the number of miles with autopilot-equipped hardware. It's only 100 million miles with autopilot engaged (from the article you cite). Let's say its 200 million now. They're at two confirmed deaths, which is about what you'd expect.

To the extent the numbers are statistically significant, it's worse than you'd expect. The fatality rate for Telsa drivers is 1/4 the average. Since the overwhelming majority of miles on autopilot equipped hardware are driven with autopilot disabled (per your article), that means Tesla human drivers are a lot safer than the average. So you need 1 fatality per 300-400 million miles driven just to match human Tesla drivers.